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Thu, 16 Oct 2025 03:36:33 -0700 (PDT) Received: from archie.me ([103.124.138.155]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-29099a7de2fsm25351505ad.58.2025.10.16.03.36.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 16 Oct 2025 03:36:32 -0700 (PDT) Received: by archie.me (Postfix, from userid 1000) id BA0E8400365D; Thu, 16 Oct 2025 17:36:29 +0700 (WIB) From: Bagas Sanjaya To: Linux Kernel Mailing List , Linux Documentation , Linux Serial Cc: Jonathan Corbet , Cengiz Can , Bagas Sanjaya , Tomas Mudrunka , Jiri Slaby , Greg Kroah-Hartman , =?UTF-8?q?Anselm=20Sch=C3=BCler?= , Randy Dunlap Subject: [PATCH v2] Documentation: sysrq: Rewrite /proc/sysrq-trigger usage Date: Thu, 16 Oct 2025 17:36:10 +0700 Message-ID: <20251016103609.33897-2-bagasdotme@gmail.com> X-Mailer: git-send-email 2.51.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1920; i=bagasdotme@gmail.com; h=from:subject; bh=kDg7zJyqLivY4/l1H+Tca7EYUDHaYlB7/rBvbKgyZ1U=; b=owGbwMvMwCX2bWenZ2ig32LG02pJDBkfTk76vLJPZ5VPQaZJ84M3Pv+FHGe95vrw2mjbi9/+7 3566a9b31HKwiDGxSArpsgyKZGv6fQuI5EL7WsdYeawMoEMYeDiFICJtPsy/HdfpR/hI60s31Sv Ms+45Jrfs5XmP39O7TnOeW3XjtoVq68yMqyJj+FpUuG5c3rpztKcHjs2EU/rYxsFzj5L8Zm8p29 SFxMA X-Developer-Key: i=bagasdotme@gmail.com; a=openpgp; fpr=701B806FDCA5D3A58FFB8F7D7C276C64A5E44A1D Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" /proc/sysrq-trigger usage documentation (in "On all" section) states that it is not recommended to write extra characters to it to avoid undefined behavior, which is contradictive to previous sentence that such characters are ignored. Also, in order to actually process them (as a string), prepending it with underscore is required. Rewrite the description. Link: https://lore.kernel.org/lkml/7ca05672-dc20-413f-a923-f77ce0a9d307@ans= elmschueler.com/ Signed-off-by: Bagas Sanjaya Reviewed-by: Randy Dunlap --- Changes since v1 [1]: - Rewrite the whole "On all" section (Jon, Randy) [1]: https://lore.kernel.org/linux-doc/20251008112409.33622-1-bagasdotme@gm= ail.com/ Documentation/admin-guide/sysrq.rst | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/Documentation/admin-guide/sysrq.rst b/Documentation/admin-guid= e/sysrq.rst index 9c7aa817adc72d..6157d93e03a1e2 100644 --- a/Documentation/admin-guide/sysrq.rst +++ b/Documentation/admin-guide/sysrq.rst @@ -75,16 +75,13 @@ On other submit a patch to be included in this section. =20 On all - Write a single character to /proc/sysrq-trigger. - Only the first character is processed, the rest of the string is - ignored. However, it is not recommended to write any extra characters - as the behavior is undefined and might change in the future versions. - E.g.:: + Write a single character to /proc/sysrq-trigger. E.g.:: =20 echo t > /proc/sysrq-trigger =20 - Alternatively, write multiple characters prepended by underscore. - This way, all characters will be processed. E.g.:: + If a string (multiple characters) is written instead, only the + first character is processed unless the string is prepended by + an underscore, like:: =20 echo _reisub > /proc/sysrq-trigger =20 base-commit: a1af37b935c73049c54cb1412cf0850212af420e --=20 An old man doll... just what I always wanted! - Clara